Corydoras Catfish

June 19, 2026 · Updated July 3, 2026 · 5 min read

Corydoras are peaceful, social bottom-dwelling catfish kept in groups of 6 or more, on soft sand, in a cycled tank of 20 gallons or more. They are excellent calm tankmates and clean up leftover food.

Corydoras are small, armored, bottom-dwelling catfish from South America, and one of the most useful peaceful community fish. They potter along the substrate all day, sifting for food, and get along with almost everything.

Corydoras are shoaling catfish from South American rivers and streams; keep a group of six or more.⁴

Groups and tank size

Corydoras are social shoalers — keep 6 or more. In a group they forage and play in the open; alone they hide. See the full breakdown by tank size in how many corydoras in a tank. A group of the common species wants a 20-gallon or larger footprint for floor space, though dwarf species like the pygmy corydoras suit a 10-gallon. For the full size table by species, see how big do corydoras get.

"If you are starting off with this species, buy at least half a dozen, as with most Corys, they are happier in their own company."

Substrate and water

Use soft sand. Corydoras feed by sifting substrate through their barbels, and sharp gravel grinds those barbels down and invites infection. They like soft to neutral, stable water around 72-80 F — see the full corydoras water parameters breakdown.² A few species have their own quirks — the panda corydoras, for example, prefers the cooler end (72-77 °F), while sterbai corydoras handle up to 82 °F (great with discus) and the subtropical peppered corydoras tolerate cool, even unheated tanks. Good filtration and clean substrate matter because they live at the bottom where waste settles.

Popular corydoras species

There are over 160 corydoras species; these are the ones you’ll actually meet in the hobby. Care is broadly the same across them, so the differences come down to size, colour, and preferred temperature.

Bronze coryC. aeneus · the hardiest and most common; the default beginner cory. Albino coryAn albino strain of the bronze (C. aeneus); identical care. Peppered coryC. paleatus · subtropical and cold-hardy; fine in a cooler or unheated tank. Panda coryC. panda · the black-and-white favourite; prefers the cooler end (72-77 °F). Sterbai coryC. sterbai · the warm-water cory (to 82 °F); pairs with discus. Pygmy coryC. pygmaeus · a nano cory (~3 cm) that shoals in mid-water; suits a 10-gallon. Julii coryC. julii · the spotted "leopard" cory; most sold as julii are really C. trilineatus.

Species photos via Wikimedia Commons: bronze — Jofre (public domain); albino — Leonardo Da Silva (CC BY 2.0); peppered — Alter welt (CC BY-SA 4.0); panda — Giniro (CC BY 3.0); sterbai — Tino Strauss (CC BY-SA 3.0); pygmy — Birger A (CC BY-SA 3.0); julii — Kai Schreiber (CC BY-SA 2.0).

Diet

They are bottom feeders, so make sure food reaches them: sinking pellets or wafers, plus frozen bloodworms and the leftovers other fish miss. They help clean up, but they are not a cleanup crew that lives on scraps alone; feed them directly. Despite common belief, corydoras do not eat algae.

Behaviour and the air-pump question

Corydoras are busy, social, and genuinely entertaining. In a group they forage out in the open, dash around, and pile up to rest, and many keepers find they quickly learn the feeding routine. They are also facultative air-breathers: every so often a cory shoots to the surface, gulps a mouthful of air, and darts back down. That is normal, not distress, because they can absorb oxygen through their gut as a backup. It also means a corydoras tank does not need an air pump, as long as the water is clean, well-filtered, and the surface stays reachable. The exception is the whole group gulping at the surface non-stop, which signals poor water or low oxygen, so test it.

Lifespan and breeding

Corydoras are long-lived for small fish. The common species often reach 10-15 years with good care, while nano species like the pygmy live around 3-4. See the full corydoras lifespan by species breakdown.

Breeding follows one genus pattern: a large, cooler water change triggers spawning, the female sticks her eggs to the glass and fine-leaved plants, and they hatch in about three to four days.³ Once their yolk sacs are absorbed, the fry take microworm and baby brine shrimp over a thin layer of sand.³

Temperament and tankmates

Corydoras are peaceful and ignore other fish, which makes them one of the best community tankmates.³ The classic aquarium author William T. Innes described them the same way long ago: “Corydoras is a quaint little fish and very well adapted to life in the aquarium. Principally a ground-feeder, it is regarded as something of an aquarium scavenger. Quite harmless.”¹ See the full corydoras tank mates guide for the compatibility model, real-keeper companion data, and what to avoid. They are a classic choice with a betta — see the betta fish care guide.

By Yevhen Bulhakov · fishkeeper & founder, reviewed against real-tank data.
Freshwater aquarist of 8+ years.

Reviewed by Allan James (ScotCat).
Catfish expert — founder of ScotCat; Corydoras & pleco authority